William a



(No Model.)

W. A. KNOWLES.

DENTAL ENGINE.

No. 386.476. Patented July 24, 1888.1.

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FIG. 2.

UNTTED STATES PATENT @EETEE.

VILLTAM A. KNOVLES, OF ALAMEDA, CALIFORNIA.

DENTAL ENGINE.

SPECIFICATION forming part of Letters Patent No. 386,476, dated J Application filed August 25, 1887.

To all 207mm it may concern.-

Be it known that I, WILLIAM A. KNowLEs, a citizen of the United States, residing in the city and county of Alameda, in the State of California, have invented a new and useful Dental Engine, of which the following is a specification.

My invention relates to improvements in dental engines, which will be understood by reference to the accompanying drawings and the letters referring thereto.

Figure 1 is a longitudinal sectional elevation; Fig. 2, afront elevation; Fig, 3, a broken sectional elevation; Fig. 4-, a plan view.

Referring by letter to the said drawings, B indicates a slotted frame,and A a sleeve thereon, which is secured in proper position and adjusted by means of a set-screw, Z, which passes through a longitudinal slot, TV, in the said ease or frame, as more fully shown in Fig. 1 of the drawings. The forward end of this main frame or casting B is provided with a vertical annular aperture, (4, through which passes a spindle, 0, having a stop, 1), on its lower end, and this spindle is of a length sufficient to receive a hinge-bracket and drivepulley, as will be presently explained.

Q indicates a hinged bracket, which is placed upon the upper outer side of the frame B, and has an eye, I), to receive the spindle 0, whereby it is held in position. This spindle has a conical enlargement, E, above the said hinged bracket, which, in addition to furnishing a stop for the said bracket, also serves as a bearing for the horizontal drive-pulley I, which is also placed upon the said spindle, and is prevented from rising by the collar F and setscrew G. This pulley I has a circumferential groove, 0, to receive the drive belt or rope, and is also formed with a friction-wheel, J, which is designed to be placed in frictional contact with a friction-wheel on one end of the cable or burr shaft, as will be presently de scribed.

M indicates the headstock, which is hinged to the bracket Q by means of a transverse pintle, T. The cable or burr shaft has its bearing in this head M, and is provided at one end with a fixed friction-wheel, K, which engages with the horizontal friction -wheel J, journalcd on the vertical spindle G. Thejour- Serial No. 217,822. (No model.)

nal-aperture ofthe head-stock is provided with a groove, U, forming shoulders d e therein. This horizontal pintlc or wing-bolt, which passes through the aperture of the said headstock,is provided with a spline,V,which moves in the groove U as the said bolt is turned.

0 indicates a lockinglevcr, which is hinged to the under side of the hinge -bracket, as shown, and has a spring, P, interposed between the rear end of the said lever and the bracket. The forward end of this lever O is suitably curved to pass around the journal end of the head-stock and engages a shoulder, N, thereon, as more fully shown in Fig. 3 of the drawings.

The wing-bolt T is provided with a rigid collar, R, which has a cam projection, S, thereon, and is designed to engage' the biting end of the lever O and throw the same out of engagement with the shoulder N of the headstock, so that the said head-stock may be allowed to swing on the end of the bracket.

\Vhen the machineis in operation, the friction-whcels J and K engaging each other, it will be seen that the lever O is engaging the shoulder on the cross-head. It will also be seen that the bracket Q may be swung around horizontally in any desired position on the frame B without disengaging the gearing, so as to accommodate the operator in using drill; but when the wing-bolt has been turned so as to cause the cam is to engage the lever O the head-stock will be allowed to swing down and the pulley on the cable-shaft thrown out of en gagement with the drive-pulley. It will be seen that by having the spline V on the bolt T the mere turning of the said bolt in one direction will cause the spline to engage the shoulder at one end of the groove in theheadstock and raise it vertically until the engaging-lever O has been brought into action to sustain it in such position, when the grip on the bolt may be released.

Having described my invention,what I claim 1. The combination, ina dental engine,ofthe hinged bracket carrying a spring-actuated lever, a headstock journalcd thereon and having its journal-aperture grooved, the hingebolt having a spline to enter said groove, a shoulder on the said stock for the engagement bolt to disengage the said lever from the head,

of the spring actuated lever, and a cam on the substantially as specified.

2. The combination, in a dental engine, substantially as described, of thehinged bracket, the spring-pressed lever thereon, the headstock journaled on the outer end of the bracket I and having the groove in its journal-aperture, and ashoulder for the engagement of said le ver, and the hinge-bolt having a spline to enter the said groove, substantially as specified.

3. The eon1biuation,With the main frame B, 

